In the United States, many in the consumer electronics industry are unhappy with CableCARD modules. 68-pin connectorization, power supply needs, heat sinking, multiple stream management and conformance testing add significant reliability problems, complexity, and cost to digital cable TV receivers. As a consequence, companies, looking for alternatives, have proposed alternate form factor modules, smart cards, and software downloadable schemes. To date, these approaches have not gained acceptance due to market forces, regulatory hurdles, and proper configuration as will be discussed.
As of this writing, in the United States, CableCARDs are being required by the FCC for all advanced cable receivers and some waivers are being allowed for embedded conditional access installed in cable operator owned, low-end receivers. Alternative approaches that offer cheaper, more efficient and smaller form factors for conditional access (CA) may be possible while addressing legacy cable systems supporting CableCARD. The key to the success of these alternate approaches, and the subject of the invention disclosed herein, will be the support and provisioning of multiple CA approaches at the same time within a receiver. By allowing the receiver to adapt to the different CA requirements of different service providers, some that support the legacy CableCARDs and others that support alternate approaches to conditional access, consumers will have unimpeded use of their digital TV receivers across content services.
A multiple slot approach used in receivers called “Multicrypt” allows access to independent services without having the home consumer swap smart cards or Common Interface modules if only a single slot were provided. The home consumer installs different modules from the different services into different receiver slots. When accessing a particular channel, the receiver automatically chooses the appropriate module. To our knowledge, Multicrypt has only been used with smart card slots or Common Interface modules slots, and it has not been used with them at the same time or accommodated other variations of CA adapters.
It is helpful to note that there are generally two aspects to conditional access (CA) processing. The first aspect is key management which derives or calculates the CA decryption key needed to descramble content. The other aspect is the stream descrambling itself. Some conditional access solutions rely on proprietary descrambling algorithms to prevent hardware cloning. And so, some solutions, using modules, combine the two aspects, key management and stream descrambling in a user replaceable device, while, other solutions just implement the key management aspect and can be replaced using devices such smart card or downloadable software. In some instances, the security of those approaches is enhanced by tying the key management to a one-time programmable (OTP) key and ladder built into the descrambler hardware of the receiver. These and other distinctions will be made clear in the following description.